1. What is a water ecosystem?

2. Unit Standards
5.L.4A.1
Analyze and interpret data to summarize the abiotic factors (including quantity of light and water, range of temperature, salinity, and soil composition) of different terrestrial ecosystems and aquatic ecosystems.
5.L.4A.2
Obtain and communicate information to describe and compare the biotic factors (including individual organisms, populations, and communities) of different terrestrial and aquatic ecosystems.

3. What are water ecosystems?
Most of the Earth’s surface is covered by water, but all water is not alike. About 97% of the world’s water is salty ocean water.

4. What are water ecosystems?
The other three percent is freshwater. Fresh water is water that does not contain salt, or is very low in salt. Fresh water is water that you drink.

5. What are water ecosystems?
Freshwater and saltwater organisms are organized in similar ways. The organisms in water ecosystems are divided into 3 main categories.

6. What are water ecosystems?
Plankton- creatures that drift freely in the water.
They are not able to swim. Some plankton, such as diatoms, are producers, and others are consumers, such as some animal larvae.

7. What are water ecosystems?
Nekton- larger, active swimmers in a body of water
Fish, turtles, and whales are all nekton.

8. What are water ecosystems?
Benthos- organisms that live on the bottom of a body of water.
Many benthos are scavengers or decomposers because they feed on material that floats down from shallower water.

9. What are water ecosystems?
Benthos- organisms that live on the bottom of a body of water.
Some benthos, such as oysters, fix themselves to one spot.

10. What are water ecosystems?
Benthos- organisms that live on the bottom of a body of water.
Others, like worms, burrow in the sand.

11. What are water ecosystems?
Benthos- organisms that live on the bottom of a body of water.
Many, like lobsters, walk about on the bottom of a body of water looking for food.

12. What are water ecosystems?
Like land ecosystem, biotic and abiotic determine the types of organisms that can survive in water ecosystems.
Unlike land ecosystems, water is never a limiting factor. (However, the amount of light, dissolved salt, and dissolved oxygen are important. They can also affect the types of organisms that can live in bodies of water.)

13. What are water ecosystems?
Little sunlight is able to penetrate to the bottom of a body of water. The water gets cooler and darker away from the surface.

14. What are water ecosystems?
Shallow water allows more light to penetrate. For this reason, producers that require light for photosynthesis are usually found on the surface or in very shallow water.

15. What are water ecosystems?
These same producers release oxygen during photosynthesis.
Water can also pick up oxygen from the air.

16. What are water ecosystems?
So surface and shallow water tend to have more dissolved oxygen than the deeper water.
The oxygen and nutrients from producers enable more organisms to live in the surface waters.